The main way Act-On tracks email opens is through a tracking pixel. This is a very small (1x1) image in the message body that, if loaded, indicates that the email has been opened.
Some email clients can be set so they do not download images. This includes when a message is opened in Plain Text. In these cases, Act-On can't track opens using the regular method. However, if the recipient clicks a link they will be counted as an open, even if they did not load the tracking pixel.
- A recipient opens an email 1 time and has 9 clickthroughs = 1 open
- A recipient opens an email 4 times with images disabled = 0 opens
- A recipient opens an email 1 time with images disabled and has 8 clickthroughs = 1 open
- A recipient opens an email 10 times and has 7 clickthroughs = 10 opens
Some email clients show the content of an email before it is fully opened, such as Microsoft Outlook's preview pane. If images are loaded in this view, each preview will be counted as an open.